A vehicle seat, such as an automobile seat, is required to have various functions including safety, holdability, and getting-on/off performance (easiness in getting-on/off). The vehicle seat is also often required to improve the comfortability for an occupant, such as seat comfort and vibration absorption performance. In addition, the vehicle seat, which is the larger one of the interior parts of an automobile, is required to meet various needs for its appearance and design.
A seat cover, that is, a trim cover, significantly influences the appearance and design of the vehicle seat. The trim cover, together with a frame, accounts for a high proportion of the overall cost of the vehicle seat. It is thus important to reduce the cost of the trim cover of the vehicle seat.
Therefore, efforts are being made to allow the vehicle seat, such as an automobile seat, to reduce its manufacturing cost and to satisfy its occupant comfortability and design.
As the background art of this technical field, Japanese Patent Application Laid-Open No. 2000-211048 (Patent Literature 1) is disclosed. Patent Literature 1 discloses a quilting seat material for an automobile cushion that has nonwoven fabric layers including thermoplastic fibers, the nonwoven fabric layers being stacked and fusion-bonded onto each other on the back face of an automobile cushion seat upholstery material layer. Each nonwoven fabric layer has a cured face on at least its outer layer surface side on the opposite side of the face facing the upholstery material layer. Thus, the quilting seat material can exhibit a quilting process effect.
The quilting seat material facilitates its recycleability, and is given satisfactory bumps and dips in the quilting process. Thus, the quilting seat material has high practicability and is useful.
As another background art of this technical field, Japanese Patent Application Laid-Open No. 2006-130715 (Patent Literature 2) is disclosed. Patent Literature 2 describes an interior material that is made by setting, into a die, an upholstery material in which a fabric, a cushion layer, and a back base cloth are stacked from the surface side thereof, and then by injecting a melted thermoplastic resin into the die to integrally mold the upholstery material and the thermoplastic resin. The fabric has a difference in thermal shrinkage rate in the vertical and horizontal directions. Formed are two or more dot-shaped fusion-bonded portions between the fabric and the back base cloth via the cushion layer and in the direction in which the thermal shrinkage rate is high. A recessed stripe pattern is formed on the surface of the upholstery material in such a manner that heat received from the melted thermoplastic resin that has been injected into the die biasedly shrinks the fabric between the dot-shaped fusion-bonded portions and in the direction in which the thermal shrinkage rate of the fabric is high. Thus, the interior material has bumps and dips on its surface.
In the interior material, the fabric has a difference in thermal shrinkage rate in the vertical and horizontal directions. In addition, formed are two or more dot-shaped fusion-bonded portions between the fabric and the back base cloth via the cushion layer and in the direction in which the thermal shrinkage rate is high. Further, the recessed stripe pattern is formed on the surface of the upholstery material in such a manner that heat received from the melted thermoplastic resin that has been injected into the die biasedly shrinks the fabric between the dot-shaped fusion-bonded portions and in the direction in which the thermal shrinkage rate of the fabric is high. Thus, it is possible to integrally mold the bumps and dips shape of any design on the surface of the upholstery material without post-processing unlike conventional interior materials.